Type of Document	Thesis
Author	Williams, Mitchell Duren
Author's Email Address	mdw05@fsu.edu
URN	etd-07132007-000033
Title	Characterization of Microbial Activity in Soils Nearby Landfills in Northwest Florida
Degree	Master of Science
Department	Civil and Environmental Engineering, Department of
Advisory Committee	Advisor Name Title Dr. Gang Chen Committee Chair Dr. Amy Chan Hilton Committee Member Dr. Tarek Abichou Committee Member
Keywords	pseudomonas bacillus groundwater remediation polymerase chain reaction pcr plate count sieve activity northwest florida soils soil characterization microbial engineering environmental bacteria reducing iron landfill landfills
Date of Defense	2007-07-11
Availability	unrestricted
Abstract Elevated iron concentrations have been observed in the groundwater downgradient of the landfills in Northwest Florida. It is suspected microbial mediated iron reduction should be responsible for the iron release. The purpose of this research is to characterize the microbial community in the soils nearby landfills in Northwest Florida to determine the dominant bacterial species. The iron rich soil in Northwest Florida and leachate from landfills are considered the primary contributors to the elevated iron concentrations observed in groundwater. Iron reducing bacteria are capable of releasing soluble Fe (II) by reducing Fe (III) bound to the soil minerals. The leachate has potential for providing carbon sources for the reaction, allowing the bacteria to more rapidly reduce the iron in the soil. In this research, the soils from sixteen landfills (fifteen Northwest Florida counties) were characterized through sieve analysis and the bacteria were quantified and identified. Traditional plate count method was used for bacterial quantification and morphology by means of microscopy and Polymerase Chain Reaction (PCR) were utilized for bacterial identification. The plate counts resulted in 0.03 million to 2.0 million colony-forming units (CFU) per gram of soil. The identification through morphology found typical rod and cocci bacteria to be the dominating species. Although potentially iron reducing bacteria were identified through morphology, they were not confirmed through DNA analysis. They need further enriched culturing in order to observe obvious iron reducing. The PCR analysis identified typical soil bacteria, Bacillus subtilis, Bacillus cereus, Bacillus thuringiensis, and Pseudomonas aeruginosa. These bacteria are common soil bacteria that are well characterized. The sieve analysis of the soils showed a correlation of increased bacterial population in well-graded soils. The soils also showed an increase in water content when there was a higher percentage of finer particles. However, increased water content and finer particles resulted in lower bacterial populations. Further studies are currently underway to quantify the iron release from the soils and the effects the leachate have on the bacterial processes.
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